JP2003178448A - Optical information recording method, optical information recording/reproducing device and optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfactorily record an information signal on an optical informa tion recording medium provided with a plurality of rewritable information recording layers. <P>SOLUTION: A plurality of kinds of recording pulse control regulations defining a waveform of the recording pulse corresponded to the information signal to be recorded are preliminarily recorded on the optical disk 1. At recording on the optical disk 1, the information is recorded by using such a recording pulse that the temperature change of the recording layer due to the convergence of light beams becomes cool timewise more rapidly for the 2nd information recording layer 23 near to the light incident side than for the 1st information recording layer 21 farmost from the light incident side. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium having a plurality of information recording layers, an optical information recording method for recording information on the optical information recording medium, and an optical information recording / reproducing apparatus.

[0002]

2. Description of the Related Art In recent years, optical discs capable of recording and reproducing information signals such as video or audio signals have been actively developed.
Among them, an optical disc in which two information recording layers are laminated to double the recording capacity is a DVD (Digital Versa).
A playback-only version of the tile disc) has already been commercialized. In such an optical disc having a plurality of information recording layers, as described in, for example, Japanese Patent Application Laid-Open No. 54-130902 (Patent Document 1), a sufficient amount of light is applied to a recording layer farther from the incident light source side. The recording layer in front is made semi-transparent in order to reach.

On the other hand, there is a phase change type optical disc as one of optical disc media capable of high density recording. The recording of data on the phase-change optical disk is performed by irradiating a rotating disk with a laser beam focused on a beam spot having a diameter of 1 μm or less, and heating and melting the recording film. The temperature reached and the cooling process of the recording film differ depending on the intensity of the recording laser light, and a phase change of the recording film occurs between the crystalline state and the amorphous state.

When the laser light is strong (this is called a peak power level), the recording film is heated to a temperature higher than its melting point and melted, and then rapidly cooled, so that it becomes amorphous. When the laser light has a medium intensity (this is referred to as a bias power level), the recording film is kept above the crystallization temperature and below the melting point so that it is crystallized. The amorphized portion is called a mark, and the crystallized portion is called a space. A method of recording data by giving information on the lengths of the marks and spaces is called a mark edge recording method. Phase change optical discs can be melted at a peak power level to form marks regardless of whether the recording film is in an amorphous state or a crystalline state, so that one beam spot erases old data and writes new data. It is possible to perform recording simultaneously, that is, direct overwrite.

For reproduction, weak laser light is irradiated so that the recording film does not cause a phase change, and the intensity of the reflected light is detected by a photodetector. Depending on the material of the recording film and the configuration of the protective layer, the reflectance of the amorphized mark portion can be greatly changed from the reflectance of the crystallized space portion,
As a result, it is possible to obtain the reproduction signal of the recorded data by detecting the difference in the reflected light amount between the mark portion and the space portion.

Various proposals have been made for applying such a phase change optical disk to the above-mentioned two-layer optical disk.
For example, Japanese Unexamined Patent Application Publication No. 2000-311346 (Patent Document 2) proposes optimizing the recording power of laser light for each layer because the recording layers are different for each recording layer. Further, in Japanese Patent Application Laid-Open No. 2000-260060 (Patent Document 3), by applying a crystallization promoting film and an optical enhancing film, it is possible to stably provide a non-reflecting film without using a reflective film for the recording layer in front. Techniques have been proposed that enable the recording of information by causing changes between crystallites and crystals.

[0007]

[Patent Document 1] Japanese Patent Laid-Open No. 54-130902

[0008]

[Patent Document 2] Japanese Unexamined Patent Publication No. 2000-311346

[0009]

[Patent Document 3] Japanese Patent Laid-Open No. 2000-260060

[0010]

However, JP-A-54-
In JP-A-130902 (Patent Document 1), a study for reproduction only is mainly conducted, and a study on a rewritable medium having a practically sufficient value of light transmission, absorption, and reflectance has not been sufficiently conducted. In the technique disclosed in Japanese Unexamined Patent Publication No. 2000-311346 (Patent Document 2), the recording pulse of the same pattern is used for a plurality of recording layers, and the peak power is merely optimized for each layer. In addition, Japanese Patent Laid-Open No. 2000-260
The technique disclosed in Japanese Unexamined Patent Publication No. 060 (Patent Document 3) has a problem in that the number of production steps increases because the configuration of the optical disc becomes complicated.

The present invention has been made in consideration of the above points, and has an optical information recording medium having a plurality of rewritable information recording layers and capable of favorably recording an information signal, and an optical information recording medium. It is an object of the present invention to provide a method and an apparatus for satisfactorily recording an information signal on a dynamic information recording medium.

[0012]

In order to achieve the above object, an optical information recording method according to the present invention comprises a recording layer that causes a physical state change due to a local temperature change due to the condensing of a light beam. An optical information recording method for recording an information signal on an optical information recording medium having N information recording layers (N is an integer of 2 or more) having a plurality of recording pulse control rules defining a recording pulse waveform. From the step of selecting a recording pulse control rule according to the information recording layer to be recorded, by modulating the intensity of the light beam according to the recording pulse determined by the selected recording pulse control rule, A step of recording an information signal on the recording layer, of the N information recording layers, the layer farthest from the incident side is the first information recording layer, and the second, ... Information recording of N Then, the recording pulse control rule selected at the time of recording on the second, ..., N information recording layer is applied when recording on the information recording layer having the same thermal characteristics as the first information recording layer. In comparison with the recording pulse control rule selected when recording on the first information recording layer, it corresponds to a recording pulse waveform that makes the temperature change of the recording layer steeper during cooling.

The optical information recording / reproducing apparatus according to the present invention comprises:
An information signal is recorded on an optical information recording medium having N information recording layers (N is an integer of 2 or more) having a recording layer that causes a physical change in temperature due to a local temperature change caused by condensing a light beam. Which is an optical information recording / reproducing device that does, from a plurality of recording pulse control rules that determine the waveform of the recording pulse,
By irradiating a rule selection unit that selects a recording pulse control rule according to the information recording layer to be recorded, and a light beam whose intensity is modulated according to the recording pulse defined by the selected recording pulse control rule, An optical recording unit for recording an information signal on the recording layer, and of the N information recording layers, a layer farthest from the incident side is a first information recording layer,
Assuming that the second, ... Nth information recording layers are arranged in order from the side closer to the incident side, the rule selection unit is the same as the first information recording layer when recording on the second, ... Nth information recording layers. When applied to recording on an information recording layer having thermal characteristics, the temperature change of the recording layer due to the focusing of the light beam, as compared with the recording pulse control rule selected at the time of recording on the first information recording layer. It is characterized in that a recording pulse control rule is selected so as to be steeper during cooling.

The optical information recording medium according to the present invention has an N information recording layer (N layer) having a recording layer that causes a physical state change due to a local temperature change due to the condensing of a light beam.
Is an integer greater than or equal to 2), and an optical information recording medium in which an information signal is recorded by modulating the intensity of a light beam, the recording pulse control rule information defining a waveform of a recording pulse for modulating the light beam is previously stored. Of the N information recording layers, the layer farthest from the incident side is the first information recording layer, and the second, ... Nth information recording order is closer to the incident side. If it is a layer, the recording pulse control rule used for the second, ..., N information recording layers is
When used in an information recording layer having the same thermal characteristics as that of the first information recording layer, the temperature of the recording layer by condensing the light beam is higher than that of the recording pulse control rule used in the first information recording layer. It is characterized in that the change becomes steeper during cooling.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings as appropriate. In the following embodiments, an optical disc having two information recording layers will be described as an example of an optical information recording medium using a phase change recording material that records by changing the actual reflectance. .

FIG. 1 shows the configuration of an optical disk device according to an embodiment of the present invention. This optical disk device 19 is
Information is recorded and reproduced using the optical disc 1. The optical disc 1 includes a first information recording layer 21 and a second information recording layer 2
3, and information tracks are formed on each information recording layer. Data recording and reproduction are performed by laser irradiation by the optical head 4.

The optical disk device 19 includes an optical head 4, a reproduction amplifier 5, a reproduction signal processing circuit 6, a focus control circuit 7, a tracking control circuit 8, a system controller 9, a recording signal processing circuit 10, a pulse setting circuit 11 and a laser driving circuit. It has twelve.

The optical head 4 irradiates the first or second information recording layer of the optical disc 1 with a laser beam having a reproducing intensity by a semiconductor laser and an objective lens which are not shown.
The optical head 4 also receives the laser light reflected from the optical disc 1.

The reproduction amplifier 5 amplifies the light detection signal output from the optical head 4 and outputs it as a reproduction signal. The reproduction signal processing circuit 6 performs waveform equalization, binarization, synchronization, demodulation, decoding, etc. on the reproduction signal supplied from the reproduction amplifier 5, and outputs it as digital data such as video, audio or computer data to an external host computer. 14 or output to the outside as an analog video / audio signal via a DA converter (not shown).

The focus control circuit 7 directs the laser spot emitted from the optical head 4 to the first information recording layer 21.
Alternatively, the position is controlled on the second information recording layer 23, and the tracking control circuit 8 controls the position of the spot on the information track.

The recording signal processing circuit 10 receives recording data such as video, audio or computer data from the host computer 14, encodes and modulates it, and outputs it as binary data. Pulse setting circuit 11
Converts the binarized data into recording pulses according to a desired conversion rule and outputs the recording pulses. The laser drive circuit 12 outputs a drive current to the semiconductor laser of the optical head 4 in response to the received recording pulse, and causes the optical head 4 to irradiate a laser beam having a recording intensity.

The system controller 9 obtains address information indicating the current position of the laser spot from the reproduction data output from the reproduction signal processing circuit, and also performs focus control so that the laser spot is located on the information track of the desired information recording layer. A control signal is output to the circuit 7 and the tracking control circuit 8. In addition, a control signal is output to the laser drive circuit 12 so that the optical head 4 irradiates the laser light with the light intensity for reproduction or recording. Further, a control signal is output to the pulse setting circuit 11 so as to select a different conversion rule depending on the type of the information recording layer.

The host computer 14 is located outside the optical disk device 19 and inputs / outputs information signals and control data such as digital audiovisual data and computer data.

FIG. 2 is a radial cross-sectional view schematically showing the laminated structure of the optical disc 1 used in the embodiment of the present invention. This optical disc is provided with two information recording layers. As shown in the figure, in an optical disc, a first information recording layer 21, an optical separation layer 22, a second information recording layer 23, and a light transmitting layer 24 are sequentially laminated on a supporting substrate 20. Each of the two information recording layers 21 and 23 provided with the optical separation layer 22 interposed therebetween is composed of a plurality of optical thin films, and information is recorded in these information recording layers.

The first information recording layer 21 is the first reflective layer 2
5, the protective layer 26, the interface layer 27, the first recording layer 28, the interface layer 29, and the protective layer 30 are sequentially laminated. The second information recording layer 23 is formed by sequentially stacking a second reflective layer 31, a protective layer 32, an interface layer 33, a second recording layer 34, an interface layer 35 and a protective layer 36. Laser light for recording and reproduction is made incident from the side of the light transmission layer 24.

The supporting substrate 20 is made of polycarbonate or PM.
It is made of a resin plate such as MA, an ultraviolet curable resin, a glass plate, or an inorganic material, and the surface of the substrate is covered with spiral or concentric continuous grooves (guide grooves, tracks). After depositing the first information recording layer 21 on the support substrate 20, an optical separation layer 22 whose surface is covered with spiral or concentric continuous grooves (guide grooves, tracks) is formed by the 2P method, and further. The second information recording layer 23 is formed thereon. After that, the light transmission layer 24 is formed by a spin coating method or a resin sheet.

The material of the protective layers 26, 30, 32, 36 is
It is physically and chemically stable, that is, it has a higher melting point and softening temperature than the material used for the first recording layer 28 and the second recording layer 34, and does not form a solid solution with the recording layer material. Is desirable. For example, Al ₂ O ₃ , SiOx, Ta ₂ O
₅ , MoO ₃ , WO ₃ , ZrO ₂ , ZnS, AlN _x , B
It is made of a dielectric material such as N, SiN _x , TiN, ZrN, PbF ₂ , MgF ₂ or a suitable combination thereof. Further, when the protective layers 26, 30 and the protective layers 32, 36 are made of different materials, there is an advantage that the degree of freedom in thermal and optical disc design is increased. Of course, the same material may be used.

The interfacial layers 27, 29, 33, 35 are thin films of nitrides or carbides provided for suppressing mutual diffusion of the elements constituting the layers on both sides thereof, for example, the general formulas X--N and X. It is a material represented by -ON. However, X is preferably a material containing at least one element of Ge, Cr, Si, Al, and Te, but is not essential. By providing this interface layer, the elements constituting the first and / or second recording layers 28, 34 and the protective layers 26, 30, 3
Mutual diffusion with the elements forming the dielectric layers of 2, 36 is suppressed, and the repetitive characteristics of recording and erasing are improved. The effect of the interface layer is described in detail, for example, in JP-A-4-52188.

The material for the first recording layer 28 and the second recording layer 34 may be any substance that causes a structural change between a crystalline state and an amorphous state, and is mainly Te, In or Se. It is a phase change material as a component. The main components of well-known phase change materials are Te-Sb-Ge, Te-Ge,
Te-Ge-Sn, Te-Ge-Sn-Au, Sb-S
e, Sb-Te, Sb-Se-Te, In-Te, In
-Se, In-Se-Te, In-Sb, In-Sb-
Se, In-Se-Te, etc. are mentioned. The first and second recording layers 28 and 34 are usually formed in an amorphous state, absorb energy such as laser light and crystallize, and optical constants (refractive index n, extinction coefficient k) change. To do.

The optical separation layer 22 is the first information recording layer 21.
Is an intermediate layer arranged between the second information recording layer 23 and the second information recording layer 23, and when reproducing the first information recording layer and the second information recording layer respectively, reproduction signals from other information recording layers are recorded. It is provided to make the impact negligible. The thickness of the optical separation layer 22 is usually 10 μm or more and 50 μm
Hereafter, it is preferably 20 μm or more and 40 μm or less. The material used for the optical separation layer 22 may be any material that is transparent to the wavelength of the laser beam with which the first information recording layer 21 is irradiated to record / reproduce signals. The material is, for example, an epoxy-based ultraviolet curable resin or the like, or a sheet-shaped double-sided tape for laminating optical disks.

First reflective layer 25 and second reflective layer 31
Is a metal element such as Au, Al, Ni, Fe, Cr and Ag or an alloy thereof. The first reflective layer 25 is
The first recording layer 28 is preferably provided in order to increase the light absorption efficiency. The second reflective layer 31 is the second
It is desirable to provide in order to secure the light quantity for the reproduction signal of the information recording layer 23, but in order to enable recording and reproduction to the first information recording layer 21, it is essential that a part of the laser beam is transmitted. . The second reflective layer 31 may be omitted,
In that case, it is necessary to select the material and thickness of the remaining layers so that sufficient reflected light can be obtained from the second information recording layer 23.

The above-mentioned first recording layer 28 and second recording layer 3
4, protective layers 26, 30, 32, 36, interface layers 27, 2
9, 33, 35, the first reflective layer 25, the second reflective layer 31
The formation of each layer such as, usually, electron beam evaporation method,
Sputtering method, ion plating method, CVD
Method, laser sputtering method or the like is applied.

Next, the operation of the optical disk device 19 configured as described above will be described by returning to FIG.

First, when the optical disk 1 is loaded, the host computer 14 sends a command indicating the reproduction mode to the system controller 9. System controller 9
Outputs a control signal to a spindle motor, a focus control circuit 7, a tracking control circuit 8 and a laser drive circuit 12, which are not shown, in response to a command indicating the reproduction mode. After the spindle motor starts rotating the optical disc 1, the laser drive circuit 12 enters the reproduction mode, and the optical head 4 irradiates the laser beam with a constant reproduction power level. The system controller 9 also sends a control signal to a transfer motor (not shown) so that the beam spot is directed to the optical disk 1.
The optical head 4 is moved in the radial direction of the disk so that the optical head 4 is on the control data area.

Next, the position of the beam spot in the focal direction (focus direction) is controlled. That is, the focus control circuit 7 selects the first or second information recording layer according to the control signal from the system controller 9, and the beam spot is moved onto it. After that, by the tracking control circuit 8, the disk radial direction (tracking direction)
Position control is performed. The position control of the beam spot in the focus direction is realized by general focus control such as the astigmatism method, and the position control in the tracking direction is realized by the general tracking control method such as the push-pull method. The description is omitted. With these position controls, the beam spot can follow the information track.

In the control data area, information on the recording pulse control rule relating to the optimum recording pulse waveform for each information recording layer is stored in advance in the form of uneven pits, meandering guide grooves, or amorphous recording marks. The laser light modulated by these returns to the optical head 4. The recording pulse control rule is to write a recording mark of a predetermined length on an information track in accordance with the length of a section in which bit 1 or bit 0 of binary data to be recorded follows. It defines the number, height, width or output timing, and is also called a recording strategy. The recording pulse control rule information stored in the control data area of each information recording layer may be the recording pulse control rule itself suitable for the information recording layer, or the recording pulse control rule suitable for the information recording layer. It may be a number or the like for specifying. In the latter case, the optical disc device 1
In FIG. 9, the numbered recording pulse control rules are stored in advance, and at the time of recording, the recording pulse control rules corresponding to the recording pulse control rule information read from the control data area of the information recording layer to be recorded are recorded on the optical disc. Device 1
The recording pulse control rule stored in No. 9 will be selected. Further, in the control data area of each information recording layer, information of at least one recording pulse control rule suitable for recording on the information recording layer may be stored.

The laser light returned to the optical head 4 is received by the photodetector of the optical head 4 and converted into an electric signal, which is amplified by the reproducing amplifier 5 and then reproduced as a reproduced signal processing circuit 6 as a reproduced signal. Output to. The reproduction signal processing circuit 6 performs waveform equalization, binarization, synchronization, demodulation, decoding, etc. on the analog reproduction signal, extracts control data, and outputs it to the system controller 9. Based on the obtained control data, the system controller 9 reads the above-mentioned recording pulse control rule from the semiconductor memory of the optical disk device 19 or the like, and sends the recording pulse control rule to the pulse setting circuit 11.

Now, the recording pulse control rule in this embodiment will be described with reference to FIG. In the same figure, (a) is a waveform diagram showing the recording data input to the pulse setting circuit 11 in binary, and shows the Hi level and the L level.
It is a binary o level. As will be described later, a Hi level section is represented by a mark and a Lo level section is represented by a space on the disc. (B) is a pulse setting circuit 1
In the waveform diagram of the recording pulse output by No. 1, one or a plurality of short pulse trains correspond to one recording mark.
The space section is held at a level corresponding to the intensity Pb (referred to as bias power). Next, in the pulse train corresponding to each mark, the pulse of the first intensity Pp (referred to as peak power) is the first pulse, the remaining comb-shaped pulse (intensity Pp) is the subpulse, and the intensity Pc following the last subpulse is Pc. The pulse (called cooling power) is called a cooling pulse. The intensity Pbo (referred to as the bottom power level) is maintained between the sub-pulses, but here it is assumed to be equal to the bias power Pb. (C) is a schematic view of a recording mark formed on a recording layer as seen from directly above.

Further, in the figure, the left side shows the case where an information signal is recorded on the first information recording layer 21, and the right side shows the case where an information signal is recorded on the second information recording layer 23. The recording pulse control rules for the same binarized data are different between the two, and the latter is different from the former in that after the recording layer material is heated to a high temperature by the laser beam during recording,
The recording pulse waveform is such that the temperature drops sharply. That is, in the waveform (recording waveform A) on the left side in (b) of the same figure, the emission intensity changes by switching between the bias power (Pb) and the peak power (Pp) higher than Pb. On the right side (recording waveform B), a section emitting light with a cooling power (Pc) lower than Pb is
It is added at the end of the first pulse or short pulse train. This is called a cooling pulse. As a result, the irradiation power decreases to the intensity Pc immediately after the intensity Pp.
Compared to the waveform on the left, which only drops to b, the temperature drop from the high temperature state becomes sharper.

The reason why the recording pulse control rules are different in this way is as follows. In an optical disc having a plurality of information recording layers, it is essential that the information recording layer on the front side be semitransparent in order to allow light to reach the information recording layer on the back side when viewed from the laser light incident side. For that purpose, usually, the reflective layer or the recording layer of the information recording layer on the front side is thinned,
Or it needs to be deleted. However, the reflective layer not only reflects the laser light but also has a role as a heat sink for rapidly returning the temperature of the recording layer to a normal temperature. Therefore, when the reflective layer is thinned or removed, the heat dissipation characteristics of the entire information recording layer deteriorate. On the other hand, the information recording layer at the back does not need to be semi-transparent, so the reflective layer can be made thicker,
The heat dissipation effect can be increased sufficiently.

Therefore, in the present embodiment, the recording pulse control rule is different between the first information recording layer 21 and the second information recording layer 23, and the recording pulse in the latter is stronger than that in the former. The emission intensity is greatly reduced immediately after the Pp pulse. Therefore, the low heat dissipation characteristic of the second information recording layer 23 itself is compensated, the cooling rates at the time of both recording become substantially equal, and even if the same recording layer material and layer structure are used, both information recording layers can be recorded. Similar recording marks can be formed in the layers. The emission intensity Pc is predetermined in consideration of the cooling rate required for forming the recording mark and the thermal characteristics of the second information recording layer 23.

The operation of the optical disk device 19 for recording information on the optical disk 1 will be described below. The system controller 9 moves the optical head 4 so that the beam spot comes to the track of the recording learning area provided in the information recording layer to be recorded on the optical disc 1. Next, a control signal is sent to the recording signal processing circuit 10 and the pulse setting circuit 11 so as to output test pattern data for recording learning. Based on the drive pulse from the laser drive circuit 12, the optical head 4 emits laser light modulated between power levels, and a mark corresponding to the test pattern is recorded on the recording layer. When the recording of the test pattern is completed, the system controller 9 shifts to the reproduction mode, sends a control signal to the laser drive circuit 12, and lowers the intensity of the laser light emitted by the optical head 4 to the reproduction power level. Then, the actuator of the optical head 4 is controlled to return the beam spot to the position of the test pattern recorded on the recording layer. The laser beam applied to the recorded test pattern is modulated by the test pattern and then returned to the optical head 4, received by the photodetector and output as a reproduction signal. The reproduction signal processing circuit 6 performs waveform equalization, binarization, synchronization, demodulation, decoding, etc. on the reproduction signal amplified by the reproduction amplifier 5. At the same time, the reproduction signal processing circuit 6 measures the modulation degree, error rate, synchronization jitter, edge shift, etc. of the reproduction signal. Recording and reproduction of the above test pattern are repeated while changing the emission intensity Pp or Pb, and the modulation degree,
If the error rate or jitter falls below the desired threshold,
The system controller 9 ends the record learning process.

At this time, when the pulse setting circuit 11 performs the first trial writing in the learning process for each information recording layer,
The recording pulse control rule selected based on the recording pulse control rule information read from the control data area of the information recording layer is used. When learning is performed in the second information recording layer 23, the recording pulse control rule is used so that the temperature change in the recording layer becomes more rapid than that in the first information recording layer 21. Further, as a result of the recording learning in the second information recording layer 23, when the measurement target such as the modulation degree, the error rate, the jitter, etc. does not fall within the allowable range, a more rapid recording pulse is selected from among a plurality of recording pulse control rules. The recording rule may be re-executed by selecting the control rule, or the learning may be repeated in order from the recording pulse control rule with the most rapid cooling from the beginning. Further, if the learning in the time axis direction of the recording pulse waveform is performed by finely adjusting not only the irradiation power of the light beam but also the edge position of each recording pulse according to the target mark length (that is, Tp, Ts If parameters are also learned), the quality of the recording signal is further improved. Also,
The frequency characteristics of the reproduction signal processing circuit such as an equalizer may be optimized.

After the laser light intensity for recording is determined in this manner, the mode is shifted to the information signal recording mode. The system controller 9 informs the recording signal processing circuit 10, the pulse setting circuit 11, and the laser driving circuit 12 that it is in the recording mode of the information signal, and moves the beam spot to the information signal area of the information recording layer to be recorded. .
When the position control of the beam spot is completed, the information to be recorded output from the host computer 14, for example, the information signal such as digitized video / audio data or computer data is transmitted to the recording signal processing circuit 10 and the pulse setting circuit 11. After that, it is sent to the laser drive circuit 12 as multi-pulse modulated data. The laser drive circuit 12 causes the optical head 4 to emit laser light, and a recording mark having an appropriate length is formed on the optical disc 1.

On the other hand, the reproduction of the information signal is performed as follows. The laser beam applied to the optical disk 1 is modulated by the recording mark, returned to the optical head 4, and sent to the reproduction signal processing circuit 6 via the reproduction amplifier 5. The reproduction signal processing circuit 6 performs waveform equalization, binarization, synchronization, demodulation, and error correction, and outputs the reproduction data to the host computer 14.

Next, actually using the apparatus of FIG. 1, the light of FIG.
An information signal was recorded on the disc and reproduced. Record and
The laser light used for reproduction is a GaN-based semiconductor with a wavelength of 400 nm.
And the NA of the objective lens of the optical head 4 is 0.
It was set to 85. Information signal is 8-16, RLL (2,10)
It was recorded by modulating with the modulation method of. Jitter is the playback signal
After binarizing, measure the difference with the clock signal of the reproduction PLL.
And display the ratio with the reference clock cycle T as a percentage.
It was TA520 of Yokogawa Electric Corp. is used for the measurement of jitter.
I used it. Regarding the allowable value of jitter, for example, the DVD standard
Is less than 9%, which is also the case in the present embodiment.
Use the value of as a guide for the allowable jitter value. Reference clock
The period T is 13.6 nsec, and the recording and reproducing linear velocity is
5.0 m / s, shortest recording mark pitch is 0.20 μm
And The optical disk 1 was manufactured as follows. support
The substrate 20 has a diameter of 120 mm and a thickness of 1.1 mm.
Using a polycarbonate plate, a spiral width of 0.
22um, pitch 0.32um, depth 22nm groove
I made it. The first information recording layer 21 is a surface of the supporting substrate 20.
The first reflective layer 25 made of AgPdCu is formed on the surface by 10
0 nm, ZnS-SiO ₂The protective layer 26 consisting of 15n
5 nm of the interface layer 27 made of Ge, GeSbTe
The first recording layer 28 made of 12 nm is made of GeN.
5 nm of interface layer 29, ZnS-SiO₂Protective layer consisting of
It was formed by depositing 30 in order of 60 nm.
Then, the first recording layer 28 is irradiated with a laser beam so as to
After changing from the rufus state to the crystalline state and initializing,
Optical separation layer 22 in which a groove shape similar to that of the support substrate 20 is transferred
Was formed. Furthermore, Ag is used as the second information recording layer 23.
The second reflective layer 31 made of PdCu is formed to have a thickness of 6 nm and ZnS-
SiO₂The protective layer 32 consisting of 12 nm is made of GeN.
The interface layer 33 having a thickness of 5 nm is made of GeSbTe.
The recording layer 34 has a thickness of 6 nm, and the GeN interface layer 35 has a thickness of 5 nm.
m, ZnS-SiO₂A protective layer 36 of 45 nm,
The films were formed in order. After forming the film, the second recording layer 34 is irradiated with laser light.
Irradiation changes the state from amorphous to crystalline.
Initialized. Finally light transmission made of polycarbonate
Layer 24 was adhered with a UV curable resin. Adhesive part and light transmission
The thickness of the overlayer 24 is 85 μm in total, and the thickness of the optical separation layer 22 is
The thickness was 30 μm. With the optical disc 1 of the present embodiment
Pp, Pb and Pc are paired with the first and second information recording layers.
And about 10, 4, 4 mW and 8, 4, 0.6, respectively.
The signal can be rewritten in mW and the reproduction power is approx.
It was 0.6 mW. The disk having the above-mentioned structure
The second information recording layer 21 has a reflectance of about 20%.
The reflectance and the transmittance of the layer 23 are about 6% and about 50%, respectively.
It was good. Therefore, through the second information recording layer 23
The effective reflectance of the obtained first information recording layer 21 is about 5%.
Met.

Table 1 shows measured values of the reproduction signal jitter of each information recording layer when the information signal was recorded and reproduced under the above conditions. In the second information recording layer 23, a jitter of 9% or less cannot be obtained by using the recording waveform A shown in FIG. 3, whereas a good jitter value of 9% or less is obtained by using the recording waveform B. Has been obtained. On the other hand, in the first information recording layer 21, a jitter of 9% or less is obtained when the recording waveform A is used, but a higher jitter value is obtained when the recording waveform B is used.

[0048]

[Table 1] 4 and 5 are waveform charts showing other examples of the recording pulse waveform in the embodiment of the present invention. In the figure, (a)
Shows a recording pulse corresponding to the shortest recording mark, and (b) shows a recording pulse corresponding to a relatively long recording mark. The columns from C to I are recording pulses when each is based on different recording pulse control rules. All of these recording pulses are designed to be more rapidly cooled when used for the second information recording layer 23 than the recording pulse A shown in FIG.

First, the waveform C is P lower than the bias power level Pb between the sub-pulses of the recording pulse waveform B of FIG.
Since it was dropped to c, it was cooled more rapidly than the waveform B. Here, the lengths (time) of the head pulse and the cooling pulse are Tp and Tc, respectively, and the lengths (time) between the sub-pulses and the sub-pulses are Ts and Tb, respectively. The irradiation intensity of the laser, that is, the pulse height is Pp1 in the head pulse and the sub-pulse, Pc in the cooling pulse and the sub-pulse, and Pb in the other sections.
In the waveform D, Tp and Ts are shorter than the recording pulse waveform A of FIG. 3, and their pulse height Pp2 is higher than the peak power level Pp1 of the waveform A. Tb is longer than that of the waveform A, and the cooling effect is promoted. Since the waveforms C and D are considered so that the temperature drop after melting of the recording film becomes more rapid than the waveform A, these waveforms are provided in the second information recording layer 23. Waveform A at 21
By applying respectively, the information signal can be satisfactorily recorded in both layers.

Next, the waveform E of FIG. 4 has a longer Tc than the waveform C. Further, in the waveform F, the cooling pulse height Pc and the bottom pulse height Pbo are lower than the waveform C. Further, in FIG. 5, the waveform G has a narrower leading pulse than the waveform C. The waveform H is the same as the waveform G except that the length of the bottom pulse immediately after the head pulse is long. Waveform I drops to Pc between sub-pulses of waveform D and adds a cooling pulse. The above waveforms E, F, G, H, and I are all waveforms such that the recording film is cooled more rapidly than the waveform C. Therefore, the waveform C may be applied to the first information recording layer 21 and the waveform E, F, G, H or I may be applied to the second information recording layer 23. Further, it is possible to select a waveform having a different cooling effect from these waveforms and use a pulse capable of cooling more rapidly in the second information recording layer 23. In this case, a recording material or a layer structure having a relatively low heat conduction efficiency can be applied to the first information recording layer 21 as well, so that the degree of freedom in designing the optical disc 1 is increased.

Table 2 shows an example of recording pulse control rule information to be stored in the control data area of the optical disc 1. In the table, the first and second information recording layers 21 and 2 are
3 shows specific parameters of the recording pulse to be used. In the table, Pp, P
b, Pc, Tp, Ts, Tb and Tc are shown in FIGS.
It is the same as the symbol shown in. The numbers in the columns of Pp, Pb, and Pc are the heights of recording pulses, which are the powers of the laser light in mW, and Tp, Ts, Tb, and Tc are the widths of recording pulses, in nsec. In the table, the recording pulse waveform represented by the parameters in the table, that is, the waveform A, is used for the first information recording layer, and is represented by the parameters in the table for the second information recording layer. It shows that the recording pulse waveform, that is, the waveform B is used. Table 3 shows another example of the recording pulse control rule information. In the table, the first
The recording pulse waveform represented by the parameters in the table, that is, the waveform G is used for the information recording layer of No. 1, and the recording pulse waveform represented by the parameters in the table is used for the second information recording layer.
That is, it indicates that the waveform I is used. In addition, Tp,
Ts, Tb, and Tc may be represented not only by the absolute value of the pulse width, but also in the form of a multiple of the reference clock period (for example, 1T or 0.5T).

Further, instead of storing various parameters of the recording pulse as recording pulse control rule information in the control data area of the optical disc 1 as shown in Table 2, a unique number is assigned to each recording pulse waveform. The optical disc device 1 determines which waveform corresponds to that number.
If it is stored in the memory of 9, only the waveform number may be stored in the control data area.

[0053]

[Table 2]

[0054]

[Table 3] As described above, in the present embodiment, the laser emission pulse is switched to the two information recording layers, and the second heat radiation property is low.
Since the light-emission pulse is selected so that the recording film of the information recording layer is cooled more rapidly, the recording mark can be favorably formed on the optical disc having the two information recording layers. Therefore, the recording quality of the two-layer optical disc is improved.

In this embodiment, as shown in FIG. 2 for the structure of the optical disc, the thickness of the reflection layer is set to the first and second values.
The case where the information recording layer and the information recording layer are made different has been described, but the present invention is not limited to this. For example, in order to improve the transmittance of the second information recording layer 23, the second reflective layer 31 itself may be deleted, or the material of the second reflective layer 31 may be changed to the same thickness. It may be transparent.

The recording pulse control rules are not limited to those shown in FIGS. 3 to 5, and there are two types of recording pulse control rules, one of which has a temperature in the recording layer more than the other. It suffices if the recording pulse waveform is such that the temperature rises to the melting temperature and then drops sharply.

In the above embodiment, the control data area of each information recording layer stores the recording pulse control rule information of each layer. However, the control data area of one information recording layer is shown. In addition, the recording pulse control rule information of all the information recording layers may be stored. In this case, there is an effect that the recording pulse control rule information for all the information recording layers can be obtained by one access.

Further, although the present embodiment has explained the case of an optical disc having two information recording layers, the basic idea is the same as that of the former case even when it has three or more information recording layers. That is, when there are three or more information recording layers, it is necessary to increase the transmittance except for the layer farthest from the laser beam incident side. Therefore, as described above, it is necessary to make the reflective layer thin, and as a result, the heat dissipation characteristics deteriorate. Therefore, if the recording pulse waveform is selected so that the recording pulse used for the other layers is more rapidly cooled than the recording pulse used for the information recording layer farthest from the laser incident side, all the information recording layers are selected. It becomes possible to record the information signal satisfactorily.

FIG. 6 shows, by way of example, an optical disc having four information recording layers. In FIG. 6, the support substrate 2
0, the first information recording layer 21 and the first optical separation layer 3
9, the second information recording layer 23, the second optical separation layer 40, the third information recording layer 41, the third optical separation layer 42, the fourth information recording layer 43, and the light transmission layer 24 are sequentially laminated. It The four information recording layers 21, 23, 41, and 43 provided with the optical separation layers 39, 40, and 42 interposed therebetween each include a plurality of optical thin films, and the first information recording layer 21 is the first
The reflective layer 25, the protective layer 26, the interface layer 27, the first recording layer 28, the interface layer 29, and the protective layer 30 are sequentially laminated. In addition, the second information recording layer 23 is the second reflective layer 3
1, the protective layer 32, the interface layer 33, the second recording layer 34, the interface layer 35, and the protective layer 36 are sequentially stacked.
Furthermore, the third information recording layer 41 includes a third reflective layer 44,
Protective layer 45, interface layer 46, third recording layer 47, interface layer 4
8 and the protective layer 49 are sequentially laminated. The fourth information recording layer 43 is formed by sequentially stacking a fourth reflective layer 50, a protective layer 51, an interface layer 52, a fourth recording layer 53, an interface layer 54 and a protective layer 55. Laser light for recording and reproduction is made incident from the side of the light transmission layer 24.

In the four-layer structure as shown in the figure, the innermost information recording layer 21 as seen from the incident side is the three information recording layers 4.
Since the laser beam must be made incident through 2, 40 and 39, the transmittance of the information recording layer must be made greater toward the front. In addition, it is preferable that the reflected light from each information recording layer be substantially equal. For this purpose, it is necessary to increase the reflectance as the information recording layer is deeper. In the configuration of FIG. 2, the second reflective layer 31 and the second recording layer 34 are included.
Both have a thickness of 6 nm, but in the configuration of FIG. 6, in the third information recording layer 41, either the third reflection layer 44 or the third recording layer 47 is thinner than that, for example, the third A configuration is conceivable in which the recording layer 47 is set to 3 nm to increase the transmittance. Further, although the cooling characteristic is sacrificed, a configuration in which the third or fourth reflective layer is deleted to increase the transmittance can be considered. As described above, it is preferable that the thickness of the reflective layer or the recording layer be thicker toward the back and thinner toward the front. Therefore, since the heat dissipation characteristics are lower in the front layer,
It is better to use a steeper recording pulse. As an example,
In the waveform I, the pulse widths Tp and Ts may be made narrower in the front layer, or the peak power Pp2 may be set higher in the front layer. As a result, the change in light intensity during recording becomes sharp, and a sufficient cooling rate can be obtained in the recording layer even in the front layer, so that a recording mark having a sufficient size can be formed.

The thermal characteristics of the first information recording layer differ greatly from those of the other information recording layers, and the thermal characteristics of the second, third and fourth information recording layers are not so different from each other. In this case, the recording pulses used in the latter three information recording layers may be substantially the same as long as the recording pulses whose laser light intensity changes are steeper than those used in the first information recording layer. I don't care.

[0062]

According to the present invention, the recording pulse control rule is selected according to the information recording layer, and the recording pulse is selected so that the information recording layer having a low heat dissipation property is cooled more rapidly. An information signal can be satisfactorily recorded on the optical information recording medium having the information recording layer of.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc device to which an optical information recording / reproducing method according to an embodiment of the present invention is applied.

FIG. 2 is a radial cross-sectional view showing an outline of a laminated structure of an optical disc used in an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a recording pulse control rule in the embodiment of the present invention.

FIG. 4 is a waveform chart showing another example of the recording pulse waveform in the embodiment of the present invention.

FIG. 5 is a waveform chart showing another example of the recording pulse waveform in the embodiment of the invention.

FIG. 6 is a radial cross-sectional view showing the outline of the laminated structure of the optical disc used in the embodiment of the present invention.

[Explanation of symbols]

1 optical disc 21 First Information Recording Layer 23 Second Information Recording Layer 4 optical head 5 playback amplifier 6 Playback signal processing circuit 7 Focus control circuit 8 Tracking control circuit 9 System controller 10 Recording signal processing circuit 11 Recording pulse setting circuit 12 Laser drive circuit 14 Host computer input / output circuit 19 Optical disk device 28 First recording layer 34 Second recording layer

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5D029 JB13                 5D090 AA01 BB05 BB12 CC01 DD03                       EE02 GG33 KK05                 5D119 AA23 BA01 BB04 BB13 DA01                       HA47

Claims (31)

[Claims] 1. An optical information recording medium provided with an N information recording layer (N is an integer of 2 or more) having a recording layer in which a physical state is changed by a local temperature change caused by condensing a light beam. An optical information recording method for recording an information signal on a recording pulse, the step of selecting a recording pulse control rule according to an information recording layer to be recorded from a plurality of recording pulse control rules defining a recording pulse waveform, Recording an information signal on the recording layer by modulating the intensity of the light beam in accordance with a recording pulse defined by a selected recording pulse control rule. , The layer farthest from the incident side is the first information recording layer, and the layers closer to the incident side are the second, ...
Assuming that it is the Nth information recording layer, the recording pulse control rule selected when recording on the second, ..., Nth information recording layer is the first
When applied to recording on an information recording layer having the same thermal characteristics as that of the information recording layer, the temperature change of the recording layer compared to the recording pulse control rule selected at the time of recording on the first information recording layer. An optical information recording method characterized in that it corresponds to a recording pulse waveform which becomes steeper during cooling. 2. The information signal is represented by the length of a mark section and a space section on the recording layer, and the recording pulse control rule is the number of recording pulses for recording a mark of a predetermined length, The optical information recording method according to claim 1, wherein the height, width, or output timing is determined. 3. The optical information recording method according to claim 2, wherein the marks corresponding to the same information signal are recorded in substantially the same shape in each information recording layer. 4. The optical information recording method according to claim 1, wherein as the optical information recording medium, a medium whose recording layer is formed of a phase change material that changes state between amorphous and crystalline is used. 5. The optical information recording method according to claim 1, wherein a medium in which the second, ..., N information recording layers partially transmit a light beam is used as the optical information recording medium. 6. At least one of the plurality of recording pulse control rules is a peak power level sufficient to melt the recording layer, a bias power level sufficient to crystallize the recording layer,
And a pulse corresponding to a recording pulse waveform that modulates the intensity of a light beam in a mark section between cooling power levels lower than the two power levels, and a pulse corresponding to the cooling power level is at least the peak power level and The optical information recording method according to claim 4, wherein the optical information recording method is arranged immediately after a pulse train of a bias power level. 7. At least one of the plurality of recording pulse control rules is recording for modulating the intensity of a light beam in a mark section among the peak power level, the bias power level, the cooling power level, and the bottom power level. 7. The optical information recording according to claim 6, which is a pulse waveform and corresponds to a recording pulse waveform which alternately switches the intensity of a light beam between the peak power level and the bottom power level in at least a part of a mark section. Method. 8. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer has a cooling power level section of a recording pulse waveform used for the first information recording layer. The optical information recording method according to claim 6 or 7, which corresponds to a recording pulse waveform having a longer cooling power level section. 9. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer is higher than the cooling power level of the recording pulse waveform used for the first information recording layer. 9. The optical information recording method according to claim 6, which corresponds to a recording pulse waveform having a low cooling power level. 10. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer comprises:
The total length of the bottom power level sections corresponds to a recording pulse waveform longer than the total length of the bottom power level sections of the recording pulse waveform used for the first information recording layer,
The optical information recording method according to claim 7. 11. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer comprises:
11. The optical information recording method according to claim 7, which corresponds to a recording pulse waveform having a bottom power level lower than the bottom power level in the recording pulse waveform used for the first information recording layer. 12. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer,
The recording pulse waveform having a peak power level section shorter than the peak power level section in the recording pulse waveform used for the first information recording layer, which corresponds to the recording pulse waveform.
The optical information recording method described in. 13. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layers,
A recording pulse waveform having a plurality of bottom power level sections for a predetermined mark, wherein a first bottom power level section in the mark section is a recording pulse used in recording the predetermined mark on the first information recording layer. The optical information recording method according to claim 7, which corresponds to a recording pulse waveform longer than the first bottom power level section. 14. The method further comprises a learning step of determining an optimum intensity of a light beam for recording an information signal, wherein during the recording on the second, ... N information recording layers, the recording layer is included in the learning step. 14. A recording pulse control rule in which the temperature change in is steeper during cooling is preferentially selected from a plurality of recording pulse control rules, and trial writing is performed according to the selected recording pulse control rule. The optical information recording method as described in 1 above. 15. An optical information recording medium provided with an N information recording layer (N is an integer of 2 or more) having a recording layer that causes a physical state change due to a local temperature change caused by condensing a light beam. An optical information recording / reproducing apparatus for recording an information signal on a recording medium, which selects a recording pulse control rule according to an information recording layer to be recorded from a plurality of recording pulse control rules which define a recording pulse waveform. Section, and an optical recording section for recording an information signal on the optical information recording medium by irradiating a light beam whose intensity is modulated according to the recording pulse defined by the selected recording pulse control rule, Of the N information recording layers, the layer farthest from the incident side is the first information recording layer, and the second, ...
Assuming that the Nth information recording layer is used, the rule selecting section records in the information recording layer having the same thermal characteristics as that of the first information recording layer when recording in the second, ..., Nth information recording layer. Applied to the first information recording layer, the recording pulse control makes the temperature change of the recording layer due to the focusing of the light beam sharper during cooling, as compared with the recording pulse control rule selected at the time of recording on the first information recording layer. An optical information recording / reproducing apparatus characterized by selecting a rule. 16. An information signal is represented by a length of a mark section and a space section on an optical information recording medium, and the recording pulse control rule is a recording pulse of a recording pulse for recording a mark of a predetermined length. The optical information recording / reproducing apparatus according to claim 15, wherein the number, height, width or output timing is determined. 17. The marks corresponding to the same information signal,
The optical information recording / reproducing apparatus according to claim 16, wherein the information recording layers are recorded in substantially the same shape. 18. The optical information recording / reproducing apparatus according to claim 15, wherein as the optical information recording medium, a medium whose recording layer is formed of a phase-change type material that changes states between amorphous and crystalline is used. 19. The optical information recording / reproducing apparatus according to claim 15, wherein a medium in which the second, ..., N information recording layers partially transmit a light beam is used as the optical information recording medium. 20. At least one of the plurality of recording pulse control rules has a peak power level sufficient to melt the recording layer, a bias power level sufficient to crystallize the recording layer, and a power level higher than the two power levels. A pulse corresponding to the recording pulse waveform that modulates the intensity of the light beam in the mark section between the low cooling power levels, and the pulse corresponding to the cooling power level is arranged immediately after the pulse train of at least the peak power level and the bias power level. 19. The optical information recording / reproducing apparatus according to claim 18, which is: 21. At least one of the plurality of recording pulse control rules modulates the intensity of a light beam in a mark section between the peak power level, the bias power level, the cooling power level, and the bottom power level. 21. The optical information recording according to claim 20, which is a pulse waveform and corresponds to a recording pulse waveform which alternately switches the intensity of a light beam between the peak power level and the bottom power level in at least a part of a mark section. Playback device. 22. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer comprises:
22. The optical information recording / reproducing apparatus according to claim 20 or 21, which corresponds to a recording pulse waveform having a cooling power level section longer than a cooling power level section of a recording pulse waveform used for the first information recording layer. 23. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer,
23. The optical information recording / reproducing apparatus according to claim 20, which corresponds to a recording pulse waveform having a cooling power level lower than the cooling power level of the recording pulse waveform used for the first information recording layer. 24. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer,
The total length of the bottom power level sections corresponds to a recording pulse waveform longer than the total length of the bottom power level sections of the recording pulse waveform used for the first information recording layer,
The optical information recording / reproducing apparatus according to claim 21. 25. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer,
25. The optical information recording / reproducing apparatus according to claim 21 or 24, which corresponds to a recording pulse waveform having a bottom power level lower than a bottom power level in the recording pulse waveform used for the first information recording layer. 26. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer,
The optical information recording / reproducing apparatus according to claim 20 or 21, which corresponds to a recording pulse waveform having a peak power level section shorter than the peak power level section in the recording pulse waveform used for the first information recording layer. 27. At least one of the recording pulse control rules selected at the time of recording on the second, ..., N information recording layer comprises:
A recording pulse waveform having a plurality of bottom power level sections for a predetermined mark, wherein a first bottom power level section in the mark section is a recording pulse used in recording the predetermined mark on the first information recording layer. 22. The optical information recording / reproducing apparatus according to claim 21, which corresponds to a recording pulse waveform longer than the first bottom power level section. 28. A learning unit for determining an optimum intensity of a light beam for recording an information signal is further provided, and at the time of recording on the second, ... 28. The recording pulse control rule in which the temperature change in is sharper during cooling is preferentially selected from a plurality of recording pulse control rules, and trial writing is performed according to the selected recording pulse control rule. 2. An optical information recording / reproducing device according to item 1. 29. An information recording layer having N recording layers (N is an integer of 2 or more) having a recording layer that causes a physical change in temperature due to a local temperature change caused by condensing the light beam is provided. An optical information recording medium in which an information signal is recorded by modulation, comprising a control data area in which recording pulse control rule information defining a waveform of a recording pulse for modulating the light beam is previously stored, Of the information recording layers, the layer farthest from the incident side is the first information recording layer, and the second, ...
Assuming that the Nth information recording layer is used, the recording pulse control rule used for the second, ..., Nth information recording layer, when used for the information recording layer having the same thermal characteristics as the first information recording layer,
An optical information recording medium, characterized in that the temperature change of the recording layer due to the focusing of the light beam is made sharper during cooling, as compared with the recording pulse control rule used for the first information recording layer. 30. An information signal is recorded as a length of a mark section and a space section, and the recording pulse control rule is the number, height, width or output of recording pulses for recording a mark of a predetermined length. 30. The optical information recording medium according to claim 29, wherein the timing is set. 31. The optical information recording medium according to claim 29, wherein a phase change material that causes a state change between amorphous and crystal is used as a material of the recording layer.